package ek.ao;

import java.io.File;
import java.util.Enumeration;
import java.util.Hashtable;

import javax.swing.filechooser.FileFilter;

/**
 * A convenience implementation of FileFilter that filters out all files except for those type
 * extensions that it knows about.
 * 
 * Extensions are of the type ".foo", which is typically found on Windows and Unix boxes, but not on
 * Macinthosh. Case is ignored.
 * 
 * Example - create a new filter that filerts out all files but gif and jpg image files:
 * 
 * JFileChooser chooser = new JFileChooser(); ExampleFileFilter filter = new ExampleFileFilter( new
 * String{"gif", "jpg"}, "JPEG & GIF Images") chooser.addChoosableFileFilter(filter);
 * chooser.showOpenDialog(this);
 * 
 * @version 1.13 06/13/02
 * @author Jeff Dinkins
 */
public class MyFileFilter extends FileFilter {

    private Hashtable<String, FileFilter> filters = null;

    private String description = null;

    private String fullDescription = null;

    private boolean useExtensionsInDescription = true;

    /**
     * Creates a file filter. If no filters are added, then all files are accepted.
     * 
     * @see #addExtension
     */
    public MyFileFilter() {
        this.filters = new Hashtable<String, FileFilter>();
    }

    /**
     * Creates a file filter that accepts files with the given extension. Example: new
     * ExampleFileFilter("jpg");
     * 
     * @see #addExtension
     */
    public MyFileFilter(String extension) {
        this(extension, null);
    }

    /**
     * Creates a file filter that accepts the given file type. Example: new ExampleFileFilter("jpg",
     * "JPEG Image Images");
     * 
     * Note that the "." before the extension is not needed. If provided, it will be ignored.
     * 
     * @see #addExtension
     */
    public MyFileFilter(String extension, String description) {
        this();
        if (extension != null)
            addExtension(extension);
        if (description != null)
            setDescription(description);
    }

    /**
     * Creates a file filter from the given string array. Example: new ExampleFileFilter(String
     * {"gif", "jpg"});
     * 
     * Note that the "." before the extension is not needed adn will be ignored.
     * 
     * @see #addExtension
     */
    public MyFileFilter(String[] filters) {
        this(filters, null);
    }

    /**
     * Creates a file filter from the given string array and description. Example: new
     * ExampleFileFilter(String {"gif", "jpg"}, "Gif and JPG Images");
     * 
     * Note that the "." before the extension is not needed and will be ignored.
     * 
     * @see #addExtension
     */
    public MyFileFilter(String[] filters, String description) {
        this();
        for (int i = 0; i < filters.length; i++) {
            // add filters one by one
            addExtension(filters[i]);
        }
        if (description != null)
            setDescription(description);
    }

    /**
     * Return true if this file should be shown in the directory pane, false if it shouldn't.
     * 
     * Files that begin with "." are ignored.
     * 
     * @see #getExtension
     * @see FileFilter#accepts
     */
    @Override
    public boolean accept(File f) {
        if (f != null) {
            if (f.isDirectory()) {
                return true;
            }
            String extension = getExtension(f);
            if (extension != null && this.filters.get(getExtension(f)) != null) {
                return true;
            }
        }
        return false;
    }

    /**
     * Return the extension portion of the file's name .
     * 
     * @see #getExtension
     * @see FileFilter#accept
     */
    public String getExtension(File f) {
        if (f != null) {
            String filename = f.getName();
            int i = filename.lastIndexOf('.');
            if (i > 0 && i < filename.length() - 1) {
                return filename.substring(i + 1).toLowerCase();
            }
        }
        return null;
    }

    /**
     * Adds a filetype "dot" extension to filter against.
     * 
     * For example: the following code will create a filter that filters out all files except those
     * that end in ".jpg" and ".tif":
     * 
     * ExampleFileFilter filter = new ExampleFileFilter(); filter.addExtension("jpg");
     * filter.addExtension("tif");
     * 
     * Note that the "." before the extension is not needed and will be ignored.
     */
    public void addExtension(String extension) {
        if (this.filters == null) {
            this.filters = new Hashtable<String, FileFilter>(5);
        }
        this.filters.put(extension.toLowerCase(), this);
        this.fullDescription = null;
    }

    /**
     * Returns the human readable description of this filter. For example: "JPEG and GIF Image Files
     * (*.jpg, *.gif)"
     * 
     * @see setDescription
     * @see setExtensionListInDescription
     * @see isExtensionListInDescription
     * @see FileFilter#getDescription
     */
    @Override
    public String getDescription() {
        if (this.fullDescription == null) {
            if (this.description == null || isExtensionListInDescription()) {
                this.fullDescription = this.description == null ? "(" : this.description + " (";
                // build the description from the extension list
                Enumeration extensions = this.filters.keys();
                if (extensions != null) {
                    this.fullDescription += "." + (String) extensions.nextElement();
                    while (extensions.hasMoreElements()) {
                        this.fullDescription += ", ." + (String) extensions.nextElement();
                    }
                }
                this.fullDescription += ")";
            } else {
                this.fullDescription = this.description;
            }
        }
        return this.fullDescription;
    }

    /**
     * Sets the human readable description of this filter. For example: filter.setDescription("Gif
     * and JPG Images");
     * 
     * @see setDescription
     * @see setExtensionListInDescription
     * @see isExtensionListInDescription
     */
    public void setDescription(String description) {
        this.description = description;
        this.fullDescription = null;
    }

    /**
     * Determines whether the extension list (.jpg, .gif, etc) should show up in the human readable
     * description.
     * 
     * Only relevent if a description was provided in the constructor or using setDescription();
     * 
     * @see getDescription
     * @see setDescription
     * @see isExtensionListInDescription
     */
    public void setExtensionListInDescription(boolean b) {
        this.useExtensionsInDescription = b;
        this.fullDescription = null;
    }

    /**
     * Returns whether the extension list (.jpg, .gif, etc) should show up in the human readable
     * description.
     * 
     * Only relevent if a description was provided in the constructor or using setDescription();
     * 
     * @see getDescription
     * @see setDescription
     * @see setExtensionListInDescription
     */
    public boolean isExtensionListInDescription() {
        return this.useExtensionsInDescription;
    }
}
